What ABS Brakes Are and How They Work

Posted on June 05, 2018.

When you start up your car, you should see the ABS light come on for a few seconds. If this light stays on, it means a mechanic should check out your brakes because the anti-lock braking system has been disabled. However, you may be wondering: “What exactly is an anti-lock braking system?”

ABS’ purpose is to prevent the wheels from locking up, so that you can maintain steering control and your vehicle doesn’t go into an uncontrolled skid. This is necessary because a skidding wheel has less traction than a non-skidding wheel. When the anti-lock braking system senses your car is starting to slip, it adjusts brake fluid pressure independent from the amount of pressure you are applying to the brakes.

There are four major components to an anti-lock braking system. These are the speed sensors, the valves, the pump, and the controller. The speed sensor is used to determine how fast the wheel is accelerating or decelerating.

The purpose of the valves is to regulate the air pressure in the brake lines. Each valve has three positions. The first allows pressure from the main cylinder to transfer to the brakes. The second is closed. The third position allows the valve to release some of the pressure placed on the brakes. Your ABS valves will remain in the third position until your car stops. Once the pressure from the brakes has been released, the pump in an anti-lock braking system restores pressure to the brakes. The last part of the system is the controller, which is an electronic control unit that monitors each wheel’s speed sensor and will activate the ABS if a wheel begins to lose traction.

Most cars on the road today have an anti-locking braking system because it is considered one of the most important safety features in modern cars when used properly.